KNOW THE TRIGGER POINTS
What does the person dislike? Is he or she resentful in the morning or first thing Monday morning? What is the motivation for this person to be mean to you? Find that motivation and eliminate it.
IDENTIFY THE PROBLEM
You have to eliminate yourself as the cause of difficulty for that person, if that is the case. Problems at home or with health can make people cantankerous. But that is not a carte blanche to make hell for other people. If that person is simply a jerk, that should inform your strategy with them. You can use your knowledge of what is really happening to your advantage.
PRE-EMPT THEIR STRIKE
If you know what the person will do next, minimize or neutralize it by removing reasons for conflict. You must see your relationship with a difficult person like a game of chess. This will make them see how insensitive they are to people around them.
An argument make you two difficult people. Other people won’t understand your reasons for reacting. All they will see is your reaction and how bad it was. Never fall into the trap of responding rashly to difficult people.
INVOLVE A THIRD PARTY IF YOU DO NOT SUCCEED
If you fail in your attempts to work with this person, involve someone both of you respect. No one has the right to make your life on earth unbearable. Be firm on how you want to have a respectful relationship. If that fails, begin to weigh more drastic measures. Some people never realize what they are doing to other people until life kicks their butt.